Rotating hammer



Patented Apr. 6,

Y UNITED? STATES PATENT ofFrlcE.

LUD'vIK nasen, or osLo, NORWAY, -AssIGNoR 'ro A/s. FJELn'Bon. or eem.' NORWAY.

. HOT ATING c'. Appneation ined 'April 1,y

i To all 'whom imag concern:

Be it known that l, IjUDvIK'RAsoH, engineer, a subject of the King of Norway, residing at Stortingsgaten 14,0slo, Norway,

have invented new and useful Improvements in Rotating Hammers, of which the following is a specification. i f

The present invention relates to rotary.v hammers of the kind, wherein an excentrically. pivoted hammer body is Hung against an abutment byV means of centrifugal force or hammering member and is then thrown back by the strikingforce, s o. thatv the hammer body gets clear yof the said .member and may again be flung forwardly agamst the same.. z

Experience has shown that in rotary hammers of this type the vibrations producedY both during its backward throw an the free escape of air therefrom at the rear side of the hammer body. Consequently, a

shock absorbing air cushion is formed between the bottom of the compartment andthe hammer body. The braking effect taking place during the driving stroke in such an embodiment will` also arise under special conditions. For if care is taken that the air' is not quite enclosed within the sald com partment but is able to escape with a limited velocity, the compartment will contain a quantity of air of'a definite-A ressure dependent upon the escaping velocity. During the driving stroke the access of air to the` chamber will nowbe-made diiicult, because the hammer body fillsloutY substantially, the

wholefcross section of the compartment, and at the rear side of the hammer body a rarefaction of air will take place adapted to cause a braking 'inuence during the forward throw of the hammer-body, until the latter at a suitable distance .from the abutment 'gets clear of the said compartment, The

.rotation o f the carrier in combination with siled striking force.

:HAMMER Y1925. serial No. 20,016.

oscillation of. the hammer body relatively to the rot-ating carrier will result inthe hammeringmember being hit withthe dei `The explained braking method has in this connection also the' advantage as to enable an easy regulation, either by adjustingthe air passage to and from the said air com- 'i partmen-tvor by varying the effective volume of .the `air compartment by means of an adjustable auxiliary compartment.

A preferred embodiment of 'the inven--iv tion is illustrated in .the Jannexed drawing showing in Figure l diagrammatically a cross sectional viewofl a hammen device constructed in accordance therewith. Fig- -ure 2 is a part of asimilar view showing a modification.

In the drawing 'l represents the boring machine casi-ng, 2 its carryin` handle and 3 v A its knocking or hammeringmember. 4 is a carrier pivoted concentrically'in the casingI 1 and provided with a pivot' 6 mounted excentricall'y with regard to the casingandl forming the carrying pin `of the oscillatory hammer body 5 within the carrier 4 a com partment `7 is arranged, the crosssection of which is substantially lled outlbythe ham" mer body*I during its motion. 8 represents the bottom of the compartment and 9 an additional or auxiliary compartment communicating with the compartment 7 and the volume of which may be varied for linstance by a screw stopper 10 filling it more or less. If now the hammer body "1s ung back from the -striking positionshown in' full lines, it will moyefreely` until its 4upper edge covers the upper edge of the compartment T whereupon any air compression will take place on the rear 'side of the hammer body resulting ina softening'of the stroke during the motion towards the position' indicated in dotted lines, wherein the hammer body is about to be `iiung forwardly again.v

During the motionin opposite direction the hammer body is braked on account `of the air` 'rarefactiontaking place within the compartment 7 behind said body and when the vhammer body get sout from this compartment, 'it will be caused, as a consequence of its combined motion, to strike thehammering mem- E' ber 3 with a sufficient velocityto produce the desired striking effect .upon the same.

By varyingthe' volume of t11ea'ddie0na1-1fl" compartment obviousl` a variation in the A braking effect obtalned both during the j body therein.

return stroke and during the driving stroke of the hammer body.

Instead; of veecting the regulation by means of an additional compartment 9, an

adjustable air valve 11; (Figure `2) may be arranged in combination withtne com` vpartment 7 in such a manner that the adjustment takes place by controlling the air passage from and to the said compartment, when the hammer body moves back and forward therein, the adjustment taking placepreferably by a needle valve.

Having now particularly Adescribed and ascertained the nature of my said invention and in whatl manner the same is to be per- -formed I declare what I claimis:

l.. In a rotary hammer, the combmatlon of a casing, 'a hammering member movably arranged "therein, a rotating carrier arranged concentrically within the casing, av

hammer body pivotally connected with the carrier excentrically to its rotating axis so as'to strike against a portion of the hammering member once for each revolution of the carrier, an inwardly closed compartment arranged in the carrier so as to recelve the inwardly moving hammer body 'in itsI retracted Vswinging position, 'the fsaid body substantially filling out the'cross section of the compartment, the air contained in the compartment acting thereby as 'an air cushion during the inward motion of the hammer body. i

2. In a rotating'hammer, the combination of a casing, a hammering member movably( arranged therein, a rotating carrier ar-J ranged concentrically `w1th1n the casing, a

hammer body pivotally connected with the carrier excentrically to its rot-ating axis so as to strike against a'portion of the hammer- .l ing member once foreach` revolution of the carrier, an inwardly closed compartment arranged lin the carrier s'o as to receive the inwardly moving hammer bodyY in its retracted swinging position, 'the said Vbody substantially filling out the cross section f the compartment, means for controlling the air pressure prevailing in said compartment and acting 'upon the motion of the hammer 3. In al rotary hammer, the combination of a casing, a hammering member movably arranged therein, a rotating carrier -arranged concentrically within the casing, a`

hammer body pivotally connected with the carrier ercentrically to its rotating axis so as to strike against a portion of the hammeringmembcronce foreach revolution of the carrier, an inwardly closed compartment ar- .ra-nged in the carrier so as to receive the Ainwardly 'moving hammer body in its retracted swinging position, the said body substantially lling loutv the cross section of :4,5 the compartment, means adjustably controllingthe air pressure prevailing in said compartment and acting upon the motionof the hammer body therein..

4.' In a rotary, hammer, the combination of a casing, a hammering member movably arranged therein, a rotating carrier arranged concentrically within the casing, a hammer body pivotally connected with the carrier excentrically to its rotating axis so as to` strike against a portion of the hammering member once for each revolution ofthe carrier, an inwardly closed compartment arranged in the carrier so as to receive the inwardly 'moving hammer bodyH in its retracted swinging position, the said'l body substantially .filling out the cross section of the compartment, an ladditional compartment being in communication with the first mentioned compartment for controlling the ment, -arranged in the carrier so as to receive the inwardly moving hammer body in its retracted swinging position, the `said body substantially lilling out the cross section of the compartment, an .additional compart-A ment being in communication with the-r'st mentioned compartment, means for` adjusting the volume of the additional compartment, for the urpose ot' enablinga regulation of the so teninginfluence of the -main compartments upon-the hammer motion.

v 6. yIn, a rotary hammer, the combination of a casing, al hammering member mor-ably arrangedtherem, a rotating carrier arranged concentrically within the casing, a hammer body pivotally connected with Athe carrier excentrically to its rotating axis sov as to Istrike against a portion of the hammering member once for each revolution of the carrier, an mwardly closed compartment arranged in "the carrierso as toreceive the inwardly moving hammer body in its -re-- tracted swinging position, the said body substantially filling out the cross section ot thecOmpartment, an additional compartment communicating with the inner part of the main compart1nent,and provitled with an adjustable bottom for the purpose of varying the total volume. of the compare,-

ments and thereby also varying their softening influence upon'the `motion of the'h'ammer body.

7. In a rotary hammer, the-combination iso of a casing, a hammering membermovably arranged therein, a rotating carrier arranged concentricaliy within the casing, a sectorshaped hammer body pivotally connected by its hub portionwith the lcarrier excentrically to its rotating` axis so as to strike against `a portion of the hammering member' once e' for each revolution of the carrier, an inwardly closed compartment arranged in the carrier so as to receive the inwardly moving hammer body, the outer limiting sur- 'faceoof the compartment being concentrical to the hub of the hammer body, the said body Substantially filling out the c'ross section of the compartment, the aircontained `in ,the compartment acting thereby as an airv cushionduring the inward motion of the hammer body.

. 8. 'In a rotary hammer, the combination of the casing, a hammering'member movably arranged therein, a rotating carrier arranged concentrically withinthe caslng, a sectorvshaped hammer body pivotally connected by its hub portion with the 'carrier excentrically to its rotating axis 'so as to strike against a portion of the hammering member i once -for each revolution of the carrier, an

inwardly closed compartment arranged in l the carrier'soas to receive the inwardly moving hammer body, the outer limiting with an adjustable bottom for the purpose of varying the total volume of the compartments and therebyv also varying their softening influence upon the motion of the hammer body. In witness whereof I aiiix'my signature.

LUDVIK 'RASCH. 

